Cast-in-situ concrete piles

ABSTRACT

This invention relates to cast-in-situ concrete piles and methods of forming same wherein a shell section is positioned in the ground about the upper portion of a substantially rigid casing so that when the casing is withdrawn from the ground the void formed thereby is filled with concrete from the shell section, thereby preventing dirt and foreign substances from sluffing into the hole.

United States Patent 1191 Hartzell et al. 1451 June 5, 1973 [54] CAST-IN-SITU CONCRETE PILES 739,268 9 1903 Shuman ..61/53.64

1,954,188 4/1934 Thornley [75] mvemors' Hameu, Oakland; 2,421,666 6/1947 Upson etal ,.61/53.66 x

Thomas P. Schwarzer, Mlramar, Fla. FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Raymond International, Inc., New 732,494 6/1955 Great Britain ..61/S3.66

York, N.Y. Primary Examiner-Jacob Shapiro [22] Filed 1971 Attorney-Ward, McElhannon, Brooks & Fitzpatrick [21] App1.No.: 125,089

[57] ABSTRACT 52 U.S. Cl ..61/s3.64, 61 /53.66 This invention relates to CaSt-iH-Siw concrete PileS and [51] Int. Cl. ..E02d 5/38 methods of forming Same wherein a Section is [58] Field of Search ..61/53.66 53.64 P in the ground the P0190" of 61/565 5352 5352 substantially rigid casing so that when the casing is withdrawn from the ground the void formed thereby is [56] References Cited filled with concrete from the shell section, thereby preventing dirt and foreign substances from sluffing UNITED STATES PATENTS into the hole- 763,213 6/1904 Shuman ..61/53.66 X 3 Claims, 11 Drawing Figures PATENTEUJUH 5 I975 SHEET 2 OF 2 BY 750mm PScA/wezm wM/%ZMAMJ m P YCYS 1 CAST-IN-SITU CONCRETE PILES This invention relates to a method of forming cast-insitu concrete piles and, more particularly, to a method of constructing concrete piles wherein the casing used as a form for the concrete is recoverable for subsequent use at another location.

It is common practic in the cast-in-situ concrete pile art to install such piles in the ground by first installing a casing, such as by means of driving methods. This casing defines an interior cavity which is subsequently filled with concrete. Casings of this type are commonly made of steel and they have wall thicknesses which are sufficient to withstand the forces encountered during the driving operation, as well as the external forces imposed by the surrounding earth formations.

Because of the expense of steel, methods and apparatus for installing so-called shell-less type piles have been devised and utilized. According to this approach, a temporary metal casing or shell is driven into the ground and concrete is poured into the interior of same. However, rather than leaving the casing permanently in the ground as was done with earlier techniques, the temporary casing or shell is pulled upwardly before the setting of the concrete, thereby leaving a concrete pile without a protective shell. In the absence of a too-fluid soil condition or extreme back pressure, the concrete and soil will be mutually supported while the concrete sets and hardens.

However, in carrying out this latter method, a problem is created with respect to the amount of concrete required to form the pile due to the fact that a void is created by the casing wall upon removal thereof from the hole. As the casing is withdrawn, the column of fluid concrete encompassed thereby will flow downwardly and outwardly, filling the void left by the casing wall and coming into direct contact with the surrounding wall. If not enough concrete is used to fill the easing, the upper surface of the concrete will be below ground level when the casingis fully withdrawn. Such a condition would allow dirt and other material to sluff into the hole before additional concrete is added.

Heretofore, various attempts have been made to overcome this problem such as by the use of a casing which was longer than that required to achieve penetration, for containing the additional concrete required, but filling such a casing with the upper end thereof, say feet above ground level, was difficult and time-consuming. A hopper large enough to contain additional concrete was placed on the top of the casing in much the same manner as a funnel, but this too was difficult and time-consuming.

It is, therefore, an object of the present invention to provide an improved and economical method of installing a cast-in-situ concrete pile in the earth wherein the casing may be removed from the ground before the concrete hardens and wherein the hole is protected against the sluffing of dirt and other material therein.

In addition, this method provides ease of adding reinforcing steel to the butt of the pile.

This and other objects have been attained in the present invention by providing in one form thereof a method of forming a cast-in-situ concrete pile characterized by the steps of driving a substantially rigid casing into the ground, and positioning a shell section about the casing. The inner diameter of the shell section is of substantially greater magnitude than the outer diameter of the casing and the length of the shell section is substantially less than the length of the casing. The next step is pouring concrete into the casing and then removing the casing from the hole prior to the setting thereof. The concrete flows outwardly and downwardly to take up the void created by the casing walls. However, the shell section which remains in the hole is positioned such that the upper surface of the concrete does not fall below the lower end of the shell section, thereby insuring that dirty and other foreign substances will not sluff into the hole.

In another form of the invention, there is provided a new and improved cast-in-situ pile including an elongated column of concrete extending downwardly into the ground. A thin walled shell section is mounted on top of the column and it is filled with concrete. The shell section has a substantially shorter length than the length of the column and the upper end thereof extends above the surface of the ground.

There has thus been outlined rather broadly the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described more fully hereinafter. Those skilled in the art will appreciate that the conception on which this disclosure is based may readily be utilized as the basis for the designing of other structures for carrying out the several purposes of the invention. It is important, therefore, that this disclosure be regarded as including such equivalent constructions as do not depart from the spirit and scope of the invention.

Several embodiments of the invention have been chosen for purposes of illustration and description, and are shown in the accompanying drawings, forming a part of the specification, wherein:

FIG. 1 is a cross-sectional view in elevation showing a casing being installed in the ground with a shell section disposed about the upper portion thereof and prior to the placement of the shell section in the ground;

FIG. 2 is an enlarged fragmentary cross-sectional view showing details of the casing and the cooperating shell section;

FIG. 3 is a cross-sectional view in elevation similar to FIG. 1, but showing the casing and shell section fully driven into the ground;

FIG. 4 is a cross-sectional view in elevation similar to FIG. 3, but showing the casing after the interior cavity defined thereby has been filled with concrete;

FIG. 5 is a cross-sectional view in elevation similar to FIG. 4, but showing the casing partially removed from the ground with the concrete within the casing being illustrated as having flowed into the void created upon removal of the casing wall;

FIG. 6 is a fragmentary cross-sectional view in elevation showing the casing fully removed from the earth with the shell section accommodating a portion of the concrete and preventing dirt and other material from sluffing into the hole;

FIG. 7 is a cross-sectional view in elevation showing a completed pile after filling the shell section with concrete;

F IG. 8 is a sectional view in elevation showing a shell section fully driven into the ground in accordance with another form of the present invention;

FIG. 9 is an enlarged fragmentary sectional view in elevation of the lower portion of the shell section;

FIG. 10 is a sectional view in elevation showing the casing and shell section fully driven into the ground; and

FIG. 11 is a sectional view in elevation similar to FIG. Ill) but showing the casing after the interior cavity defined thereby has been filled with concrete.

Referring now to FIG. 1 of the drawing, a hollow casing 11 is illustrated as being installed in the ground or earth 12 by any conventional means (not shown) such as steam or air hammers, vibrating hammers, or resonant pile-driving devices. The casing 11 is preferably constructed of a relatively rigid material, such as steel, and the walls of the casing are of a thickness sufficient to resist the driving forces imposed thereon during installation of the casing in the ground. Although casing l 1 is illustrated as being of circular cross section, it may be of any convenient or suitable cross sectional shape or configuration. A detachable closure device 13 of any conventional construction is disposed on the lower end of casing 11 to prevent dirt or other substances from entering into the interior 14 of the casing 11 as the easing is driven into the ground. As may be seen with reference to FIGS. 1 and 2, casing 11 has fixedly disposed thereabout, as by means of welding, an annular drive collar 15 constructed of steel or other relatively strong and rigid material. Annular drive collar 15 is disposed about the casing at a preselected distance from the upper end of the casing.

Concentrically disposed about the upper portion of casing l l is a cylindrical shell section 16 which is preferably, but not necessarily, constructed of a relatively thin-walled corrugated material. The inner diameter of the shell section 16 is of greater magnitude than the outer diameter of the casing 11 with the exception of the lowermost end portion of the shell section which is turned inwardly, as at 17, so that slidable engagement is effected between the end portion and the outer surface of the casing. It should be noted that turned-in portion 17 is disposed below drive collar 15. It will be appreciated that this turned-in portion is a slidable seal wiper which prevents soil and water from entering the shell as the casing is removed. It also scrapes any soil from the casing that might otherwise adhere to it and foul the shell portion concrete.

Upon continued downward movement of casing 11, drive collar 15 contacts portion 17 of shell section 16 to drag or pull the shell section into the earth. Driving of the casing 11 is terminated before the upper end of the shell section passes under the surface of the earth, as shown in FIG. 3. The positioning of drive collar 15 on casing 11, i.e., the distance from the upper end thereof, has been selected so that casing 11 will penetrate a desired distance into the earth while at the same time ensuring that the shell section 16 still protrudes a desired distance above the surface of the earth, when the driving operation has been completed.

After the casing 11 and shell section 16 have been installed as described hereinbefore, concrete 18 is poured into the interior 14 of casing 11 until the casing is substantially filled, thereby forming an elongated concrete column in the ground, as shown in FIG. 4.

After the concrete filling operation has been carried out and before the concrete has had a chance to set up or harden, the casing 11 is pulled upwardly out of the earth as shown in FIG. 5, with the shell section 16 remaining in place in the ground. Such pulling operation may be effected by means of any suitable conventional pulling device or hoist (not shown). The closure device 13 remains in the hole since it automatically detaches itself from casing lll under the influence of the weight of the concrete column. As casing 11 is withdrawn, the concrete l8 flows downwardly and outwardly to take up the void created by the casing walls, thereby coming into contact with earth 12. This flow of concrete 18 may be quite substantial. For example, in the event that a 12 54; inch outside diameter casing with a inch wall thickness is utilized, each 7.75 feet of easing withdrawn will cause the 12 inch column of concrete inside it to drop 1 foot. Thus, upon withdrawal of a casing 40 feet long, the concrete will drop 5.16 feet; and in a casing 50 feet in length, the concrete will drop 6.45 feet; and in a 60-foot casing the concrete will drop 7.74 feet.

After casing 11 has been fully withdrawn from the ground, the concrete 18 will have dropped a substantial distance downward in the hole, as shown in FIG. 6, with the amount of slumping, of course, being dependent upon the dimensional characteristics of casing 11. The presence of shell section 16 prevents sluffing action from occurring due to the concrete drop which otherwise would leave the upper portion of the hole unprotected against the entry of dirt or other foreign material, thereby contaminating or diminishing the strength of the finished concrete pile. The length of the shell section is such that the top of the concrete remains above the bottom of the shell section.

The next step in the method of forming a cast-in-situ pile, in accordance with the present invention, is pouring additional concrete into the shell section 16 to extend the pile-to its desired length. This step is illustrated in FIG. 7. If desired, suitable reinforcing means 19 may be positioned in the hole within the shell section prior to the addition of further concrete. Concrete is allowed to set within the shell section 16, which is of relatively inexpensive construction and remains permanently installed.

In the embodiment of the invention illustrated in FIGS. 8-11, the shell section 16 is positioned in the ground prior to the driving of the rigid casing ill, as seen in FIG. 8. This could be effected by using a separate rig and a conventional pile driving core to carry it down, or it could be installed by a vibrator. In some installations, the shell is fabricated with smooth walls. If the soil in which it is installed is not water bearing, then it can be driven open ended and thence cleaned out in a conventional manner using a fluted auger. In most installations, as seen in FIGS. 8 and 9, a temporary closure is provided for the bottom of the shell section until such time as the casing section is inserted into and through it. The temporary closure includes the annular drive collar 15 which is held in position by the inwardly turned lower end portion of the shell, as at 17. The lower end portion of the shell is also provided with a lip portion 18 which holds the detachable boot plate or closure device 13 on the end of the shell to prevent soil and/or water from entering the shell.

Thereafter, as seen in FIG. 10, the rigid casing 111- is inserted into the shell section 16 and driven therethrough in such a manner as to carry the closure device 13 down with the shell, thereby forming a closure for the lower end of the casing 11 to prevent dirt or other substances from entering into the interior 14 thereof, as it is being driven into the ground. It will be appreciated that sliding engagement is effected between the drive collar and the outside of the casing 11, thereby preventing foreign matter from entering the shell section 16. The casing 11 is then driven a desired distance into the earth.

As best seen in FIG. 11, after the casing 11 and the shell section 16 have been installed in the earth, the concrete 18 is poured into the interior 14 of the casing 11 until the casing is substantially filled. After the concrete filling operation has been carried out and before the concrete has had a chance to set up or harden, the casing 11 is pulled upwardly from the earth, and the method is completed in the same manner as that described hereinbefore in connection with the embodiment of FIGS. 1-7.

It will thus be seen that the present invention does indeed provide an improved cast-in-situ concrete pile which is superior in simplicity, economy and efficiency as compared to prior art such structures.

Although several embodiments of the invention are herein disclosed for purposes of explanation, various modifications thereof, after study of this specification, will be apparent to those skilled in the art to which the invention pertains.

What is claimed and desired to be secured by letters patent is:

1. A method of forming a cast-in-situ concrete pile in the ground comprising the steps of:

mounting a shell section having a lower inwardly projecting end portion on the upper portion of a substantially rigid casing, said shell section being of a shorter length than the length of said casing and having an inner diameter of substantially greater magnitude than the outer diameter of the casing; and

mounting a drive collar on said casing adjacent the lower edge of said shell section,

driving said easing into the ground while said casing drags said shell section into the ground; said drive collar engaging said lower end portion for dragging said shell section into the ground,

pouring concrete into said casing; and

withdrawing said casing from the ground while retaining the shell section in the ground at a depth so that when said concrete flows donwardly therefrom to fill the void created by the removal of the casing the upper surface of the concrete remains above the lower end of the shell section, said step of withdrawing the casing being carried out before the concrete has hardened.

2. A method of forming a cast-in-situ concrete pile in the ground comprising the steps of:

driving an elongated rigid casing partially into the ground;

mounting a driving ring on said rigid casing adjacent the lower end of a shell section having a lower inwardly projecting end portion to slidably engage said rigid casing,

mounting said shell section on the upper portion of said casing, said shell section having a shorter length than the length of said casing and having an inner diameter of greater magnitude than the outer diameter of the casing;

driving said rigid casing further into the ground while said driving ring on said casing engages said lower end portion to drag said shell section into the ground,

pouring concrete into said casing;

withdrawing said casing from the ground while maintaining the shell section in the ground, said step of withdrawing the casing being carried out before the concrete has hardened; and

pouring additional concrete into said shell section after the casing has been withdrawn.

3. A method of forming a cast-in-situ concrete pile in the ground comprising the steps of:

driving an elongated substantially rigid casing partially into the ground;

mounting a driving ring on said rigid casing adjacent the lower end of a corrugated thin walled shell section having a lower inwardly projecting end portion to slidably engage said rigid casing,

mounting said corrugated thin walled shell section on the upper portion of said casing, said shell section having a shorter length than the length of said casing and having an inner diameter of greater magnitude than the outer diameter of the casing;

driving said rigid casing further into the ground while said driving ring on said casing engages said lower end portion to drag said shell section into the ground,

pouring concrete into said casing;

withdrawing said casing from the ground while maintaining the shell section in the ground, said step of withdrawing the casing being carried out before the concrete has hardened;

inserting reinforcing members into the concrete in said shell section; and

pouring additional concrete into said shell section after the casing has been withdrawn. 

1. A method of forming a cast-in-situ concrete pile in the ground comprising the steps of: mounting a shell section having a lower inwardly projecting end portion on the upper portion of a substantially rigid casing, said shell section being of a shorter length than the length of said casing and having an inner diameter of substantially greater magnitude than the outer diameter of the casing; and mounting a drive collar on said casing adjacent the lower edge of said shell section, driving said casing into the ground while said casing drags said shell section into the ground; said drive collar engaging said lower end portion for dragging said shell section into the ground, pouring concrete into said casing; and withdrawing said casing from the ground while retaining the shell section in the ground at a depth so that when said concrete flows donwardly therefrom to fill the void created by the removal of the casing the upper surface of the concrete remains above the lower end of the shell section, said step of withdrawing the casing being carried out before the concrete has hardened.
 2. A method of forming a cast-in-situ concrete pile in the ground comprising the steps of: driving an elongated rigid casing partially into the ground; mounting a driving ring on said rigid casing adjacent the lower end of a shell section having a lower inwardly projecting end portion to slidably engage said rigid casing, mounting said shell section on the upper portion of said casing, said shell section having a shorter length than the length of said casing and having an inner diameter of greater magnitude than the outer diameter of the casing; driving said rigid casing further into the ground while said driving ring on said casing engages said lower end portion to drag said shell section into the ground, pouring concrete into said casing; withdrawing said casing from the ground while maintaining the shell section in the ground, said step of withdrawing the casing being carried out before the concrete has hardened; and pouring additional concrete into said shell section after the casing has been withdrawn.
 3. A method of forming a cast-in-situ concrete pile in the ground comprising the steps of: driving an elongated substantially rigid casing partially into the ground; mounting a driving ring on said rigid casing adjacent the lower end of a corrugated thin walled shell section having a lower inwardly projecting end portion to slidably engage said rigid casing, mounting said corrugated thin walled shell section on the upper portion of said casing, said shell section having a shorter length than the length of said casing and having an inner diameter of greater magnitude than the outer diameter of the casing; driving said rigid casing further into the ground while said driving ring on said casing engages said lower end portion to drag said shell section into the ground, pouring concrete into said casing; withdrawing said casing from the ground while maintaining the shell section in the ground, said step of withdrawing the casing being carried out before the concrete has hardened; inserting reinforcing members into the concrete in said shell section; and pouring additional concrete into said shell section after the casing has been withdrawn. 